1. Field of the Invention
The present invention relates to method and device for smoothing enlarged characters and enlarged images for use in a printer, a graphic display and the like.
2. Description of the Related Art
For example, when outputting an enlarged character such as a twice enlarged character, a quadruply enlarged character and the like in a printer which expresses characters by means of fonts of a dot matrix type, the font of a standard character is enlarged to produce an enlarged font and characters are printed by use of the enlarged font. However, to simply enlarge the font of the standard character causes the contours of characters to be discontinuous outstandingly. Therefore, when outputting the enlarged font, the enlarged font is generally smoothed to thereby smooth the contour of the enlarged character. However, in the smoothing processing, the portions that are inherently to be right-angled must not be smoothed. Such need for smoothing exists not only in the enlarged character but also in an enlarged image such as a symbol, a figure and the like which are generated by enlarging an original bit map.
For example, in Japanese Patent Unexamined Publication No. Hei. 1-208154, there is disclosed an enlarged character smoothing method in which an enlarged character is smoothed while right-angled portions are left as it is.
According to the smoothing method disclosed in the above-mentioned publication, with respect to each of four diagonal directions, four points in the neighborhood of a character are compared with one another and dots are added to the enlarged character sequentially by use of a logical operation, thereby smoothing the oblique line portions of the enlarged character while the right-angled portions of the enlarged character are left as it is.
The smoothing method disclosed in the above publication is a method of smoothing an enlarged character with reference to the original character information, and a smoothing processing by use of a given dot pattern must be executed with respect to each of the four diagonal directions. This makes the smoothing processing complicated and it takes much time to perform the complicated smoothing processing when trying to realize the complicated smoothing processing by software.
Also, according to the above smoothing method, as the given dot pattern for use in the smoothing processing, different dot patterns must be prepared according to the enlarging magnifications of the characters, which makes it hard to smooth easily the enlarged characters that are enlarged by an arbitrary magnification or multiple number.